Handling Mohamed Salah When in the mood, the Egyptian winger can prove a right handful with his direct brand of running from the right flank.

He works off Streller really well, timing his runs to dart inside his full-back.

That could turn into a stiff challenge for Ryan Bertrand at left-back, especially if Philipp Degen, formerly of Liverpool, decides to get adventurous by going on the overlap.

This is where Chelsea need the attacking player on that side, whether it is Eden Hazard or Oscar, to stay switched on by tracking back.

A two-versus-one, after all, would not be good news.

But even if Degen stays put, Salah is lively enough to cause plenty of problems with his sharp turn of pace and nose for goal.

Testing Basle's central defenders Going forward, the Swiss champions can be extremely effective when their front three start hitting the mark.

Down the other end, however, we have seen nothing to suggest Murat Yakin’s back four rank among the best. In particular, Schär’s central defensive partner, Aleksandar Dragovic, looks a little suspect when put under pressure, as proved when an elementary mistake gifted Spurs a goal.

The big question, of course, is whether Fernando Torres can expose that weakness.

Awful against Liverpool on Sunday, he needs to do a lot better here to give his side a much-needed focal point.

That is always vital away from home. If the lone striker fails to hold up the ball and make good runs, the visitors are handicapped to a worrying degree.

Rafa's tactical stance If you can count on one thing, it is that Benítez will have done his homework meticulously on the opposition.

Nobody pays more attention to detail than the Spanish coach.

Nobody places greater store on following a tactical plan.

And while this approach can lack joie de vivre over the course of a long season, it comes into its own in these two-legged ties.

That makes Chelsea strong favourites to reach the Europa League final. Not only do they have better players, they have a more experienced manager for this situation.